Compass A Story of Exploration and Innovation Alan Gurney W.W. Norton: 320 pp., $22.95 ...

So, if you want a true heading of 90 degrees, your GPS will report a compass heading of 96 degrees—the compass-card reading, plus the magnetic variation. If the compass’s magnetic deviation is also 5 ...

Magnetic North A marine compass will have one set of magnets that is balanced to seek out magnetic north. Magnetic north is not true north — as in the North Pole — but the location of Earth’s north ...

The compass consists of a domino-sized chip filled with rubidium-87 atoms heated to exactly 113 degrees. These magnetically sensitive atoms orient themselves in certain ways when in the presence ...